Crohn's disease is an inflammatory bowel disease (IBD). It causes inflammation of your digestive tract, which can lead to abdominal pain, severe diarrhea, fatigue, weight loss and malnutrition. Inflammation caused by Crohn's disease can involve different areas of the digestive tract in different people. The inflammation caused by Crohn's disease often spreads deep into the layers of affected bowel tissue. Crohn's disease can be both painful and debilitating, and sometimes may lead to life-threatening complications.

Symptoms

In some people with Crohn's disease, only the last segment of the small intestine (ileum) is affected. In others, the disease is confined to the colon (part of the large intestine). The most common areas affected by Crohn's disease are the last part of the small intestine and the colon. Signs and symptoms of Crohn's disease can range from mild to severe. They usually develop gradually, but sometimes will come on suddenly, without warning. You may also have periods of time when you have no signs or symptoms (remission). When the disease is active, signs and symptoms may include: • Diarrhea,Fever, Fatigue, Abdominal pain and cramping, Blood in your stool, Mouth sores, Reduced appetite and weight loss, Pain or drainage near or around the anus due to inflammation from a tunnel into the skin (fistula)

Causes

The exact cause of Crohn's disease remains unknown. Previously, diet and stress were suspected, but now doctors know that these factors may aggravate but don't cause Crohn's disease. A number of factors, such as heredity and a malfunctioning immune system, likely play a role in its development. • Immune system. It's possible that a virus or bacterium may trigger Crohn's disease. When your immune system tries to fight off the invading microorganism, an abnormal immune response causes the immune system to attack the cells in the digestive tract, too. • Heredity. Crohn's is more common in people who have family members with the disease, so genes may play a role in making people more susceptible. However, most people with Crohn's disease don't have a family history of the disease.